// Copyright 2011 David Galles, University of San Francisco. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification, are
// permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of
// conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice, this list
// of conditions and the following disclaimer in the documentation and/or other materials
// provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY David Galles ``AS IS'' AND ANY EXPRESS OR IMPLIED
// WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
// FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> OR
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
// ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
// ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// The views and conclusions contained in the software and documentation are those of the
// authors and should not be interpreted as representing official policies, either expressed
// or implied, of the University of San Francisco
import { Algorithm, addControlToAlgorithmBar } from "@/components/algorithm/Algorithm";

// Constants.

var LINK_COLOR = "#007700";
var HIGHLIGHT_CIRCLE_COLOR = "#007700";
var FOREGROUND_COLOR = "#007700";
var BACKGROUND_COLOR = "#EEFFEE";
var PRINT_COLOR = FOREGROUND_COLOR;

var WIDTH_DELTA = 50;
var HEIGHT_DELTA = 50;
var STARTING_Y = 50;


var FIRST_PRINT_POS_X = 50;
var PRINT_VERTICAL_GAP = 20;
var PRINT_HORIZONTAL_GAP = 50;


export class SPLAYTREE extends Algorithm {
    constructor(am, w, h) {
        super();
        this.init(am, w, h);
    }
    init(am, w, h) {
        super.init.call(this, am);
        this.startingX = w / 2;
        this.first_print_pos_y = h - 2 * PRINT_VERTICAL_GAP;
        this.print_max = w - 10;

        this.addControls();
        this.nextIndex = 0;
        this.commands = [];
        this.cmd("CreateLabel", 0, "", 20, 10, 0);
        this.nextIndex = 1;
        this.animationManager.StartNewAnimation(this.commands);
        this.animationManager.skipForward();
        this.animationManager.clearHistory();

    }
    addControls() {
        this.insertField = addControlToAlgorithmBar("Text", "");
        this.insertField.onkeydown = this.returnSubmit(this.insertField, this.insertCallback.bind(this), 4);
        this.insertButton = addControlToAlgorithmBar("Button", "插入");
        this.insertButton.onclick = this.insertCallback.bind(this);
        this.deleteField = addControlToAlgorithmBar("Text", "");
        this.deleteField.onkeydown = this.returnSubmit(this.deleteField, this.deleteCallback.bind(this), 4);
        this.deleteButton = addControlToAlgorithmBar("Button", "删除");
        this.deleteButton.onclick = this.deleteCallback.bind(this);
        this.findField = addControlToAlgorithmBar("Text", "");
        this.findField.onkeydown = this.returnSubmit(this.findField, this.findCallback.bind(this), 4);
        this.findButton = addControlToAlgorithmBar("Button", "查询");
        this.findButton.onclick = this.findCallback.bind(this);
        this.printButton = addControlToAlgorithmBar("Button", "打印");
        this.printButton.onclick = this.printCallback.bind(this);
    }
    reset() {
        this.nextIndex = 1;
        this.treeRoot = null;
    }
    insertCallback(event) {
        var insertedValue = this.insertField.value;
        // Get text value
        insertedValue = this.normalizeNumber(insertedValue, 4);
        if (insertedValue != "") {
            // set text value
            this.insertField.value = "";
            this.implementAction(this.insertElement.bind(this), insertedValue);
        }
    }
    deleteCallback(event) {
        var deletedValue = this.deleteField.value;
        if (deletedValue != "") {
            deletedValue = this.normalizeNumber(deletedValue, 4);
            this.deleteField.value = "";
            this.implementAction(this.deleteElement.bind(this), deletedValue);
        }
    }
    //  TODO:  This top-down version is broken.  Don't use
    splay(value) {
        if (this.treeRoot == null) {
            return false;
        }
        if (this.treeRoot.data == value) {
            return true;
        }
        if (value < this.treeRoot.data) {
            if (this.treeRoot.left == null) {
                return false;
            }
            else if (this.treeRoot.left.data == value) {
                this.singleRotateRight(this.treeRoot);
                return true;
            }
            else if (value < this.treeRoot.left.data) {
                if (this.treeRoot.left.left == null) {
                    this.singleRotateRight(this.treeRoot);
                    return this.splay(value);
                }

                else {
                    this.zigZigRight(this.treeRoot);
                    return this.splay(value);
                }
            }

            else {
                if (this.treeRoot.left.right == null) {
                    this.singleRotateRight(this.treeRoot);
                    return this.splay(value);
                }

                else {
                    this.doubleRotateRight(this.treeRoot);
                    return this.splay(value);
                }

            }
        }

        else {
            if (this.treeRoot.right == null) {
                return false;
            }
            else if (this.treeRoot.right.data == value) {
                this.singleRotateLeft(this.treeRoot);
                return true;
            }
            else if (value > this.treeRoot.right.data) {
                if (this.treeRoot.right.right == null) {
                    this.singleRotateLeft(this.treeRoot);
                    return this.splay(value);
                }

                else {
                    this.zigZigLeft(this.treeRoot);
                    return this.splay(value);
                }
            }

            else {
                if (this.treeRoot.right.left == null) {
                    this.singleRotateLeft(this.treeRoot);
                    return this.splay(value);
                }

                else {
                    this.doubleRotateLeft(this.treeRot);
                    return this.splay(value);
                }

            }


        }

    }
    printCallback(event) {
        this.implementAction(this.printTree.bind(this), "");
    }
    printTree(unused) {
        this.commands = [];

        if (this.treeRoot != null) {
            this.highlightID = this.nextIndex++;
            var firstLabel = this.nextIndex;
            this.cmd("CreateHighlightCircle", this.highlightID, HIGHLIGHT_CIRCLE_COLOR, this.treeRoot.x, this.treeRoot.y);
            this.xPosOfNextLabel = FIRST_PRINT_POS_X;
            this.yPosOfNextLabel = this.first_print_pos_y;
            this.printTreeRec(this.treeRoot);
            this.cmd("Delete", this.highlightID);
            this.cmd("Step");

            for (var i = firstLabel; i < this.nextIndex; i++) {
                this.cmd("Delete", i);
            }
            this.nextIndex = this.highlightID; /// Reuse objects.  Not necessary.
        }
        return this.commands;
    }
    printTreeRec(tree) {
        this.cmd("Step");
        if (tree.left != null) {
            this.cmd("Move", this.highlightID, tree.left.x, tree.left.y);
            this.printTreeRec(tree.left);
            this.cmd("Move", this.highlightID, tree.x, tree.y);
            this.cmd("Step");
        }
        var nextLabelID = this.nextIndex++;
        this.cmd("CreateLabel", nextLabelID, tree.data, tree.x, tree.y);
        this.cmd("SetForegroundColor", nextLabelID, PRINT_COLOR);
        this.cmd("Move", nextLabelID, this.xPosOfNextLabel, this.yPosOfNextLabel);
        this.cmd("Step");

        this.xPosOfNextLabel += PRINT_HORIZONTAL_GAP;
        if (this.xPosOfNextLabel > this.print_max) {
            this.xPosOfNextLabel = FIRST_PRINT_POS_X;
            this.yPosOfNextLabel += PRINT_VERTICAL_GAP;

        }
        if (tree.right != null) {
            this.cmd("Move", this.highlightID, tree.right.x, tree.right.y);
            this.printTreeRec(tree.right);
            this.cmd("Move", this.highlightID, tree.x, tree.y);
            this.cmd("Step");
        }
        return;
    }
    findCallback(event) {
        var findValue;
        findValue = this.normalizeNumber(this.findField.value, 4);
        this.findField.value = "";
        this.implementAction(this.findElement.bind(this), findValue);
    }
    findElement(findValue) {
        this.commands = [];

        this.highlightID = this.nextIndex++;



        var found = this.doFind(this.treeRoot, findValue);

        if (found) {
            this.cmd("SetText", 0, "元素 " + findValue + " 找到。");

        }

        else {
            this.cmd("SetText", 0, "元素 " + findValue + " 未找到。");

        }


        return this.commands;
    }
    doFind(tree, value) {
        this.cmd("SetText", 0, "查询 " + value);
        if (tree != null) {
            this.cmd("SetHighlight", tree.graphicID, 1);
            if (tree.data == value) {
                this.cmd("SetText", 0, "查询 " + value + " : " + value + " = " + value + " (找到元素!)");
                this.cmd("Step");
                this.cmd("SetText", 0, "将找到的节点展开到树根");
                this.cmd("Step");
                this.cmd("SetHighlight", tree.graphicID, 0);
                this.splayUp(tree);
                return true;
            }

            else {
                if (tree.data > value) {
                    this.cmd("SetText", 0, "查询 " + value + " : " + value + " < " + tree.data + " (查询左子树)");
                    this.cmd("Step");
                    this.cmd("SetHighlight", tree.graphicID, 0);
                    if (tree.left != null) {
                        this.cmd("CreateHighlightCircle", this.highlightID, HIGHLIGHT_CIRCLE_COLOR, tree.x, tree.y);
                        this.cmd("Move", this.highlightID, tree.left.x, tree.left.y);
                        this.cmd("Step");
                        this.cmd("Delete", this.highlightID);
                        return this.doFind(tree.left, value);
                    }

                    else {
                        this.splayUp(tree);
                        return false;
                    }
                }

                else {
                    this.cmd("SetText", 0, "查询 " + value + " : " + value + " > " + tree.data + " (查询右子树)");
                    this.cmd("Step");
                    this.cmd("SetHighlight", tree.graphicID, 0);
                    if (tree.right != null) {
                        this.cmd("CreateHighlightCircle", this.highlightID, HIGHLIGHT_CIRCLE_COLOR, tree.x, tree.y);
                        this.cmd("Move", this.highlightID, tree.right.x, tree.right.y);
                        this.cmd("Step");
                        this.cmd("Delete", this.highlightID);
                        return this.doFind(tree.right, value);
                    }

                    else {
                        this.splayUp(tree);
                        return false;

                    }
                }

            }

        }

        else {
            this.cmd("SetText", 0, "查询 " + value + " : " + "< 空树 > (未找到元素)");
            this.cmd("Step");
            this.cmd("SetText", 0, "查询 " + value + " : " + " (未找到元素)");
            return false;
        }
    }
    insertElement(insertedValue) {
        this.commands = new Array();
        this.cmd("SetText", 0, "插入 " + insertedValue);
        this.highlightID = this.nextIndex++;

        if (this.treeRoot == null) {
            this.cmd("CreateCircle", this.nextIndex, insertedValue, this.startingX, STARTING_Y);
            this.cmd("SetForegroundColor", this.nextIndex, FOREGROUND_COLOR);
            this.cmd("SetBackgroundColor", this.nextIndex, BACKGROUND_COLOR);
            this.cmd("Step");
            this.treeRoot = new BSTNode(insertedValue, this.nextIndex, this.startingX, STARTING_Y);
            this.nextIndex += 1;
        }

        else {
            this.cmd("CreateCircle", this.nextIndex, insertedValue, 100, 100);
            this.cmd("SetForegroundColor", this.nextIndex, FOREGROUND_COLOR);
            this.cmd("SetBackgroundColor", this.nextIndex, BACKGROUND_COLOR);
            this.cmd("Step");
            var insertElem = new BSTNode(insertedValue, this.nextIndex, 100, 100);


            this.nextIndex += 1;
            this.cmd("SetHighlight", insertElem.graphicID, 1);
            this.insert(insertElem, this.treeRoot);
            this.resizeTree();
            this.cmd("SetText", 0, "将插入的元素展开到树根");
            this.cmd("Step");
            this.splayUp(insertElem);

        }
        this.cmd("SetText", 0, "");
        return this.commands;
    }
    insert(elem, tree) {
        this.cmd("SetHighlight", tree.graphicID, 1);
        this.cmd("SetHighlight", elem.graphicID, 1);

        if (elem.data < tree.data) {
            this.cmd("SetText", 0, elem.data + " < " + tree.data + ".  查询左子树");
        }

        else {
            this.cmd("SetText", 0, elem.data + " >= " + tree.data + ".  查询右子树");
        }
        this.cmd("Step");
        this.cmd("SetHighlight", tree.graphicID, 0);
        this.cmd("SetHighlight", elem.graphicID, 0);

        if (elem.data < tree.data) {
            if (tree.left == null) {
                this.cmd("SetText", 0, "找到空树, 插入元素");

                this.cmd("SetHighlight", elem.graphicID, 0);
                tree.left = elem;
                elem.parent = tree;
                this.cmd("Connect", tree.graphicID, elem.graphicID, LINK_COLOR);
            }

            else {
                this.cmd("CreateHighlightCircle", this.highlightID, HIGHLIGHT_CIRCLE_COLOR, tree.x, tree.y);
                this.cmd("Move", this.highlightID, tree.left.x, tree.left.y);
                this.cmd("Step");
                this.cmd("Delete", this.highlightID);
                this.insert(elem, tree.left);
            }
        }

        else {
            if (tree.right == null) {
                this.cmd("SetText", 0, "找到空树, 插入元素");
                this.cmd("SetHighlight", elem.graphicID, 0);
                tree.right = elem;
                elem.parent = tree;
                this.cmd("Connect", tree.graphicID, elem.graphicID, LINK_COLOR);
                elem.x = tree.x + WIDTH_DELTA / 2;
                elem.y = tree.y + HEIGHT_DELTA;
                this.cmd("Move", elem.graphicID, elem.x, elem.y);
            }

            else {
                this.cmd("CreateHighlightCircle", this.highlightID, HIGHLIGHT_CIRCLE_COLOR, tree.x, tree.y);
                this.cmd("Move", this.highlightID, tree.right.x, tree.right.y);
                this.cmd("Step");
                this.cmd("Delete", this.highlightID);
                this.insert(elem, tree.right);
            }
        }


    }
    deleteElement(deletedValue) {
        this.commands = [];
        this.cmd("SetText", 0, "删除 " + deletedValue);
        this.cmd("Step");
        this.cmd("SetText", 0, "");
        this.highlightID = this.nextIndex++;
        this.treeDelete(this.treeRoot, deletedValue);
        this.cmd("SetText", 0, "");
        // Do delete
        return this.commands;
    }
    treeDelete(tree, valueToDelete) {
        this.cmd("SetText", 0, "查询 " + valueToDelete + " 展开到树根");
        this.cmd("Step");

        var inTree = this.doFind(this.treeRoot, valueToDelete);
        this.cmd("SetText", 0, "除根，留下左右树");
        this.cmd("Step");
        if (inTree) {
            if (this.treeRoot.right == null) {
                this.cmd("Delete", this.treeRoot.graphicID);
                this.cmd("SetText", 0, "没有右边的树，让左边的树成为根。");
                this.cmd("Step");
                this.treeRoot = this.treeRoot.left;
                this.treeRoot.parent = null;
                this.resizeTree();
            }
            else if (this.treeRoot.left == null) {
                this.cmd("Delete", this.treeRoot.graphicID);
                this.cmd("SetText", 0, "没有左边的树，让右边的树成为根。");
                this.cmd("Step");
                this.treeRoot = this.treeRoot.right;
                this.treeRoot.parent = null;
                this.resizeTree();
            }

            else {
                var right = this.treeRoot.right;
                var left = this.treeRoot.left;
                var oldGraphicID = this.treeRoot.graphicID;
                this.cmd("Disconnect", this.treeRoot.graphicID, left.graphicID);
                this.cmd("Disconnect", this.treeRoot.graphicID, right.graphicID);
                this.cmd("SetAlpha", this.treeRoot.graphicID, 0);
                this.cmd("SetText", 0, "将左侧树中最大的元素展开到根部");
                this.cmd("Step");

                left.parent = null;
                var largestLeft = this.findMax(left);
                this.splayUp(largestLeft);
                this.cmd("SetText", 0, "左树现在没有右子树，连接左树和右树");
                this.cmd("Step");
                this.cmd("Connect", largestLeft.graphicID, right.graphicID, LINK_COLOR);
                largestLeft.parent = null;
                largestLeft.right = right;
                right.parent = largestLeft;
                this.treeRoot = largestLeft;
                this.cmd("Delete", oldGraphicID);
                this.resizeTree();

            }
        }
    }
    singleRotateRight(tree) {
        var B = tree;
        var t3 = B.right;
        var A = tree.left;
        var t1 = A.left;
        var t2 = A.right;

        this.cmd("SetText", 0, "向右弯曲");
        this.cmd("SetEdgeHighlight", B.graphicID, A.graphicID, 1);
        this.cmd("Step");


        if (t2 != null) {
            this.cmd("Disconnect", A.graphicID, t2.graphicID);
            this.cmd("Connect", B.graphicID, t2.graphicID, LINK_COLOR);
            t2.parent = B;
        }
        this.cmd("Disconnect", B.graphicID, A.graphicID);
        this.cmd("Connect", A.graphicID, B.graphicID, LINK_COLOR);
        A.parent = B.parent;
        if (B.parent == null) {
            this.treeRoot = A;
        }

        else {
            this.cmd("Disconnect", B.parent.graphicID, B.graphicID, LINK_COLOR);
            this.cmd("Connect", B.parent.graphicID, A.graphicID, LINK_COLOR);
            if (B.isLeftChild()) {
                B.parent.left = A;
            }

            else {
                B.parent.right = A;
            }
        }
        A.right = B;
        B.parent = A;
        B.left = t2;
        this.resizeTree();
    }
    zigZigRight(tree) {
        var C = tree;
        var B = tree.left;
        var A = tree.left.left;
        var t1 = A.left;
        var t2 = A.right;
        var t3 = B.right;
        var t4 = C.right;

        this.cmd("SetText", 0, "向右弯曲");
        this.cmd("SetEdgeHighlight", C.graphicID, B.graphicID, 1);
        this.cmd("SetEdgeHighlight", B.graphicID, A.graphicID, 1);
        this.cmd("Step");
        this.cmd("SetEdgeHighlight", C.graphicID, B.graphicID, 0);
        this.cmd("SetEdgeHighlight", B.graphicID, A.graphicID, 0);


        if (C.parent != null) {
            this.cmd("Disconnect", C.parent.graphicID, C.graphicID);
            this.cmd("Connect", C.parent.graphicID, A.graphicID, LINK_COLOR);
            if (C.isLeftChild()) {
                C.parent.left = A;
            }

            else {
                C.parent.right = A;
            }
        }

        else {
            this.treeRoot = A;
        }

        if (t2 != null) {
            this.cmd("Disconnect", A.graphicID, t2.graphicID);
            this.cmd("Connect", B.graphicID, t2.graphicID, LINK_COLOR);
            t2.parent = B;
        }
        if (t3 != null) {
            this.cmd("Disconnect", B.graphicID, t3.graphicID);
            this.cmd("Connect", C.graphicID, t3.graphicID, LINK_COLOR);
            t3.parent = C;
        }
        this.cmd("Disconnect", B.graphicID, A.graphicID);
        this.cmd("Connect", A.graphicID, B.graphicID, LINK_COLOR);
        this.cmd("Disconnect", C.graphicID, B.graphicID);
        this.cmd("Connect", B.graphicID, C.graphicID, LINK_COLOR);

        A.right = B;
        A.parent = C.parent;
        B.parent = A;
        B.left = t2;
        B.right = C;
        C.parent = B;
        C.left = t3;
        this.resizeTree();
    }
    zigZigLeft(tree) {
        var A = tree;
        var B = tree.right;
        var C = tree.right.right;
        var t1 = A.left;
        var t2 = B.left;
        var t3 = C.left;
        var t4 = C.right;

        this.cmd("SetText", 0, "向左弯曲");
        this.cmd("SetEdgeHighlight", A.graphicID, B.graphicID, 1);
        this.cmd("SetEdgeHighlight", B.graphicID, C.graphicID, 1);
        this.cmd("Step");
        this.cmd("SetEdgeHighlight", A.graphicID, B.graphicID, 0);
        this.cmd("SetEdgeHighlight", B.graphicID, C.graphicID, 0);



        if (A.parent != null) {
            this.cmd("Disconnect", A.parent.graphicID, A.graphicID);
            this.cmd("Connect", A.parent.graphicID, C.graphicID, LINK_COLOR);
            if (A.isLeftChild()) {
                A.parent.left = C;
            }

            else {
                A.parent.right = C;
            }
        }

        else {
            this.treeRoot = C;
        }

        if (t2 != null) {
            this.cmd("Disconnect", B.graphicID, t2.graphicID);
            this.cmd("Connect", A.graphicID, t2.graphicID, LINK_COLOR);
            t2.parent = A;
        }
        if (t3 != null) {
            this.cmd("Disconnect", C.graphicID, t3.graphicID);
            this.cmd("Connect", B.graphicID, t3.graphicID, LINK_COLOR);
            t3.parent = B;
        }
        this.cmd("Disconnect", A.graphicID, B.graphicID);
        this.cmd("Disconnect", B.graphicID, C.graphicID);
        this.cmd("Connect", C.graphicID, B.graphicID, LINK_COLOR);
        this.cmd("Connect", B.graphicID, A.graphicID, LINK_COLOR);
        C.parent = A.parent;
        A.right = t2;
        B.left = A;
        A.parent = B;
        B.right = t3;
        C.left = B;
        B.parent = C;

        this.resizeTree();

    }
    singleRotateLeft(tree) {
        var A = tree;
        var B = tree.right;
        var t1 = A.left;
        var t2 = B.left;
        var t3 = B.right;

        this.cmd("SetText", 0, "向左弯曲");
        this.cmd("SetEdgeHighlight", A.graphicID, B.graphicID, 1);
        this.cmd("Step");

        if (t2 != null) {
            this.cmd("Disconnect", B.graphicID, t2.graphicID);
            this.cmd("Connect", A.graphicID, t2.graphicID, LINK_COLOR);
            t2.parent = A;
        }
        this.cmd("Disconnect", A.graphicID, B.graphicID);
        this.cmd("Connect", B.graphicID, A.graphicID, LINK_COLOR);
        B.parent = A.parent;
        if (A.parent == null) {
            this.treeRoot = B;
        }

        else {
            this.cmd("Disconnect", A.parent.graphicID, A.graphicID, LINK_COLOR);
            this.cmd("Connect", A.parent.graphicID, B.graphicID, LINK_COLOR);

            if (A.isLeftChild()) {
                A.parent.left = B;
            }

            else {
                A.parent.right = B;
            }
        }
        B.left = A;
        A.parent = B;
        A.right = t2;

        this.resizeTree();
    }
    splayUp(tree) {
        if (tree.parent == null) {
            return;
        }
        else if (tree.parent.parent == null) {
            if (tree.isLeftChild()) {
                this.singleRotateRight(tree.parent);

            }

            else {
                this.singleRotateLeft(tree.parent);
            }
        }
        else if (tree.isLeftChild() && !tree.parent.isLeftChild()) {
            this.doubleRotateLeft(tree.parent.parent);
            this.splayUp(tree);

        }
        else if (!tree.isLeftChild() && tree.parent.isLeftChild()) {
            this.doubleRotateRight(tree.parent.parent);
            this.splayUp(tree);
        }
        else if (tree.isLeftChild()) {
            this.zigZigRight(tree.parent.parent);
            this.splayUp(tree);
        }

        else {
            this.zigZigLeft(tree.parent.parent);
            this.splayUp(tree);
        }
    }
    findMax(tree) {
        if (tree.right != null) {
            this.highlightID = this.nextIndex++;
            this.cmd("CreateHighlightCircle", this.highlightID, HIGHLIGHT_CIRCLE_COLOR, tree.x, tree.y);
            this.cmd("Step");
            while (tree.right != null) {
                this.cmd("Move", this.highlightID, tree.right.x, tree.right.y);
                this.cmd("Step");
                tree = tree.right;
            }
            this.cmd("Delete", this.highlightID);
            return tree;
        }

        else {
            return tree;
        }
    }
    doubleRotateRight(tree) {
        this.cmd("SetText", 0, "向右弯曲");
        var A = tree.left;
        var B = tree.left.right;
        var C = tree;
        var t1 = A.left;
        var t2 = B.left;
        var t3 = B.right;
        var t4 = C.right;

        this.cmd("SetEdgeHighlight", C.graphicID, A.graphicID, 1);
        this.cmd("SetEdgeHighlight", A.graphicID, B.graphicID, 1);

        this.cmd("Step");

        if (t2 != null) {
            this.cmd("Disconnect", B.graphicID, t2.graphicID);
            t2.parent = A;
            A.right = t2;
            this.cmd("Connect", A.graphicID, t2.graphicID, LINK_COLOR);
        }
        if (t3 != null) {
            this.cmd("Disconnect", B.graphicID, t3.graphicID);
            t3.parent = C;
            C.left = t2;
            this.cmd("Connect", C.graphicID, t3.graphicID, LINK_COLOR);
        }
        if (C.parent == null) {
            B.parent = null;
            this.treeRoot = B;
        }

        else {
            this.cmd("Disconnect", C.parent.graphicID, C.graphicID);
            this.cmd("Connect", C.parent.graphicID, B.graphicID, LINK_COLOR);
            if (C.isLeftChild()) {
                C.parent.left = B;
            }

            else {
                C.parent.right = B;
            }
            B.parent = C.parent;
            C.parent = B;
        }
        this.cmd("Disconnect", C.graphicID, A.graphicID);
        this.cmd("Disconnect", A.graphicID, B.graphicID);
        this.cmd("Connect", B.graphicID, A.graphicID, LINK_COLOR);
        this.cmd("Connect", B.graphicID, C.graphicID, LINK_COLOR);
        B.left = A;
        A.parent = B;
        B.right = C;
        C.parent = B;
        A.right = t2;
        C.left = t3;

        this.resizeTree();


    }
    doubleRotateLeft(tree) {
        this.cmd("SetText", 0, "向左弯曲");
        var A = tree;
        var B = tree.right.left;
        var C = tree.right;
        var t1 = A.left;
        var t2 = B.left;
        var t3 = B.right;
        var t4 = C.right;

        this.cmd("SetEdgeHighlight", A.graphicID, C.graphicID, 1);
        this.cmd("SetEdgeHighlight", C.graphicID, B.graphicID, 1);

        this.cmd("Step");

        if (t2 != null) {
            this.cmd("Disconnect", B.graphicID, t2.graphicID);
            t2.parent = A;
            A.right = t2;
            this.cmd("Connect", A.graphicID, t2.graphicID, LINK_COLOR);
        }
        if (t3 != null) {
            this.cmd("Disconnect", B.graphicID, t3.graphicID);
            t3.parent = C;
            C.left = t2;
            this.cmd("Connect", C.graphicID, t3.graphicID, LINK_COLOR);
        }


        if (A.parent == null) {
            B.parent = null;
            this.treeRoot = B;
        }

        else {
            this.cmd("Disconnect", A.parent.graphicID, A.graphicID);
            this.cmd("Connect", A.parent.graphicID, B.graphicID, LINK_COLOR);
            if (A.isLeftChild()) {
                A.parent.left = B;
            }

            else {
                A.parent.right = B;
            }
            B.parent = A.parent;
            A.parent = B;

        }
        this.cmd("Disconnect", A.graphicID, C.graphicID);
        this.cmd("Disconnect", C.graphicID, B.graphicID);
        this.cmd("Connect", B.graphicID, A.graphicID, LINK_COLOR);
        this.cmd("Connect", B.graphicID, C.graphicID, LINK_COLOR);
        B.left = A;
        A.parent = B;
        B.right = C;
        C.parent = B;
        A.right = t2;
        C.left = t3;

        this.resizeTree();


    }
    resizeTree() {
        var startingPoint = this.startingX;
        this.resizeWidths(this.treeRoot);
        if (this.treeRoot != null) {
            if (this.treeRoot.leftWidth > startingPoint) {
                startingPoint = this.treeRoot.leftWidth;
            }
            else if (this.treeRoot.rightWidth > startingPoint) {
                startingPoint = Math.max(this.treeRoot.leftWidth, 2 * startingPoint - this.treeRoot.rightWidth);
            }
            this.setNewPositions(this.treeRoot, startingPoint, STARTING_Y, 0);
            this.animateNewPositions(this.treeRoot);
            this.cmd("Step");
        }

    }
    setNewPositions(tree, xPosition, yPosition, side) {
        if (tree != null) {
            tree.y = yPosition;
            if (side == -1) {
                xPosition = xPosition - tree.rightWidth;
            }
            else if (side == 1) {
                xPosition = xPosition + tree.leftWidth;
            }
            tree.x = xPosition;
            this.setNewPositions(tree.left, xPosition, yPosition + HEIGHT_DELTA, -1);
            this.setNewPositions(tree.right, xPosition, yPosition + HEIGHT_DELTA, 1);
        }

    }
    animateNewPositions(tree) {
        if (tree != null) {
            this.cmd("Move", tree.graphicID, tree.x, tree.y);
            this.animateNewPositions(tree.left);
            this.animateNewPositions(tree.right);
        }
    }
    resizeWidths(tree) {
        if (tree == null) {
            return 0;
        }
        tree.leftWidth = Math.max(this.resizeWidths(tree.left), WIDTH_DELTA / 2);
        tree.rightWidth = Math.max(this.resizeWidths(tree.right), WIDTH_DELTA / 2);
        return tree.leftWidth + tree.rightWidth;
    }
    disableUI(event) {
        this.insertField.disabled = true;
        this.insertButton.disabled = true;
        this.deleteField.disabled = true;
        this.deleteButton.disabled = true;
        this.findField.disabled = true;
        this.findButton.disabled = true;
        this.printButton.disabled = true;
    }
    enableUI(event) {
        this.insertField.disabled = false;
        this.insertButton.disabled = false;
        this.deleteField.disabled = false;
        this.deleteButton.disabled = false;
        this.findField.disabled = false;
        this.findButton.disabled = false;
        this.printButton.disabled = false;
    }
}

class BSTNode {
    constructor(val, id, initialX, initialY) {
        this.data = val;
        this.x = initialX;
        this.y = initialY;
        this.graphicID = id;
        this.left = null;
        this.right = null;
        this.parent = null;
    }
    isLeftChild() {
        if (this.parent == null) {
            return true;
        }
        return this.parent.left == this;
    }
}

